Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Durante qual Campeonato o Oponente Jeff Borowiak estava?
 ###Tabelas: CREATE TABLE doubles:_35_20–15 (doubles:_35_20–15_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Date VARCHAR, Tournament VARCHAR, Surface VARCHAR, Partnering VARCHAR, Opponent VARCHAR, Score VARCHAR) CREATE TABLE notes_and_references (notes_and_references_id AUTO_INCREMENT PRIMARY KEY, School VARCHAR, Location VARCHAR, Total INT, Crimean War INT, Persian War INT, Indian Mutiny INT, 1860-1878 INT, Zulu War INT, Second Afghan War VARCHAR) CREATE TABLE singles:_18_8_titles_–_10_runner-ups (singles:_18_8_titles_–_10_runner-ups_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Date INT, Championship VARCHAR, Surface VARCHAR, Opponent VARCHAR, Score VARCHAR) CREATE TABLE international_broadcasts (international_broadcasts_id AUTO_INCREMENT PRIMARY KEY, Country VARCHAR, TV Network(s) VARCHAR, Series Premiere VARCHAR, Weekly Schedule VARCHAR, Status VARCHAR) CREATE TABLE properties_of_common_solvents (properties_of_common_solvents_id AUTO_INCREMENT PRIMARY KEY, Solvent VARCHAR, Chemical Formula VARCHAR, Boiling point VARCHAR, Dielectric constant VARCHAR, Density VARCHAR, Dipole moment ( D ) VARCHAR)  
SELECT Championship FROM singles:_18_8_titles_–_10_runner-ups WHERE Opponent = jeff borowiak